Quarter sheet sander

ABSTRACT

An orbital sander includes a housing, a drive unit within the housing having an electric motor defining a rotational axis, and a drive shaft coupled for co-rotation with the motor about the rotational axis having a fan rotatably coupled to the lower portion of the drive shaft. The fan includes a main body having a plurality of fan blades, an upper counterweight located on one side of the main body and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan, and an interruption region located opposite the lower counterweight with fan blades located within the interruption region having a reduced mass. The orbital sander further includes a baseplate for selectively mounting a sanding sheet that is coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to co-pending U.S. Provisional Patent Application 63/221,702 filed on Jul. 14, 2021, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a powered oscillating tool, and more particularly to a battery powered orbital sander.

BACKGROUND OF THE INVENTION

Orbital abrading machines generally include a manually manipulatable housing, a motor supported by the housing coupled to a drive shaft driven for rotation about a drive axis, and an assembly for mounting a pad for abrading a work surface for orbital movement about the drive axis. Depending on the nature of the orbit, such an abrading machine can be used for coarse abrading work or for fine abrading work.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, an orbital sander including a housing, a drive unit within the housing having an electric motor defining a rotational axis, and a drive shaft coupled for co-rotation with the motor about the rotational axis having a fan rotatably coupled to the lower portion of the drive shaft. The fan includes a main body having a plurality of fan blades, an upper counterweight located on one side of the main body and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan, and an interruption region located opposite the lower counterweight with fan blades located within the interruption region having a reduced mass. The orbital sander further includes a baseplate for selectively mounting a sanding sheet that is coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.

The present invention provides, in another aspect, an orbital sander including a housing, a drive unit within the housing having an electric motor defining a rotational axis, a drive shaft coupled for co-rotation with the motor about the rotational axis having a lower portion, and a fan rotatably coupled to the lower portion of the drive shaft. The orbital sander further includes a dust collection portion integrated with the housing for partially housing a dust collection system. The dust collection system includes a shroud portion for partially enclosing the fan to form a seal between the housing and the fan, a mating interface having a latch for selectively receiving a dust bag attachment, and a latching mechanism for hooking onto the latch to secure the dust bag attachment. The orbital sander further includes a baseplate for selectively mounting a sanding sheet that is coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.

The present invention provides, in another aspect, an orbital sander including a housing, a drive unit within the housing having an electric motor with a motor shaft extending from the motor, a drive shaft coupled to the motor and offset from the motor shaft, the drive shaft defining a rotational axis and including a lower portion, and a fan rotatably coupled to the lower portion of the drive shaft. The fan includes a main body having a plurality of fan blades, an upper counterweight located on one side of the main body, and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan. The orbital sander further includes a baseplate for selectively mounting a sanding sheet that is coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.

Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an orbital sander in accordance with an embodiment of the invention.

FIG. 2 is a perspective view of an opposite side of the orbital sander of FIG. 1 .

FIG. 3 is a cross-sectional view of a drive unit of the sander of FIGS. 1-2 .

FIG. 4A is top, perspective view of a fan of the drive unit of the sander of FIGS. 1-3 .

FIG. 4B is a bottom, perspective view of the fan of FIG. 4B.

FIG. 5A is a perspective view of a dust collection system of the sander of FIGS. 1-3 .

FIG. 5B is an exploded view of the dust collection system of FIG. 5A.

FIG. 6A is an enlarged perspective view of a front clamp of the sander of FIGS. 1-3 .

FIG. 6B is a side view of the front clamp of FIG. 6A.

FIG. 7 is an enlarged side view of a portion of a foam pad of the sander of FIGS. 1-3 .

FIG. 8A is a perspective view of a battery receptacle of the sander of FIGS. 1-2 .

FIG. 8B is an enlarged side view of the battery receptacle of FIG. 8A.

FIG. 9 is a cross-sectional view of an alternative embodiment of a drive unit for use with the sander of FIGS. 1-3 .

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

FIGS. 1-3 illustrate an orbital sander, and in particular, a quarter sheet sander 10. The quarter sheet sander 10 includes a main housing 14 that has a motor housing portion 18 that supports a direct-drive drive unit 54 (FIG. 3 ). The direct-drive unit 54 includes an electric motor 58 with a drive shaft 62 that extends along a rotational axis 66 and that rotates in response to torque from the electric motor 58. The main housing 14 further includes a handle portion 22 extending from the motor housing 18 and shaped to be grasped by a hand of the user, a battery receptacle 26 for selectively receiving a battery pack 31 (FIG. 8B) to electrically power the electric motor 58, and a dust collection portion 20 that is integrated with the housing 14 and that partially houses a dust collection system 120. The handle portion 22 includes a controller 70 (e.g., a printed circuit board having one or more microprocessors and multiple field-effect transducers to drive the motor 58), a push button switch 32 electrically connected to the controller 70 to provide an input signal to the controller 70 to activate and deactivate the motor 58 in response to actuation of the switch 32, and a push button 30 that protrudes from the handle portion 22 and that is depressible by the user to actuate the switch 32. Additionally, the handle 22 includes a speed selection switch 34 that electrically communicates with the controller 70 to selectively alter the rotational speed of the motor 58.

The sheet sander 10 also includes a baseplate 46 that supports the main housing 14 and a paper retention system including a front clamp 38 and a rear clamp 42. A foam pad 50 is attached to the baseplate 46 (e.g., via screws) and supports a sanding sheet 164 (FIG. 7 ) that is retained by the front and rear clamps 38, 42. As illustrated, the rear clamp 42 is located opposite the dust collection portion 20 of the housing 14 so that access to the clamp 42 is not obstructed by the dust collection portion 20. In some embodiments of the sander 10, the rear clamp 42 can be retained on the baseplate 46 within a groove 43 to only form a singular contact point between the rear clamp 42 and the baseplate 46 to secure the sanding sheet 164.

With continued reference to FIGS. 1-3 , the drive unit 54 includes a first bearing 74 to support a top portion of the drive shaft 62 that is retained in the motor housing 18, and a second bearing 78 that supports a lower portion 64 of the drive shaft 62. The second bearing 78 is captured by a baseplate carrier 48 formed on the baseplate 46, and the lower portion 64 of the drive shaft 62 is fastened to the baseplate carrier 48 by a fastener 49 (e.g., a screw) such that the drive shaft 62 is rotatably coupled to the baseplate carrier 48. The drive unit 54 further includes a plurality of torque absorbers 82 located on the baseplate 46. The torque absorbers 82 flex and absorb the torque from the motor 58 to prevent free rotation about the rotational axis 66. A fan 86 is positioned on the lower portion 64 of the drive shaft 62 between the second bearing 78 and the drive shaft 62 to generate a sufficient suction force to draw dust and debris through a plurality of holes 52 in the baseplate 46 during operation of the sander 10.

FIGS. 4A-4B illustrate that the fan 86 includes a main body portion 90 that has a bore 94 to receive the lower portion 64 of the drive shaft 62, a plurality of fan blades 98 generally radially disposed on the body 90 adjacent the outer periphery, an upper counterweight 102 located on one side of the body 90, and a lower counterweight 106 located on an opposite side of the body 90 relative to the side with the upper counterweight 102. Each of the counterweights 102, 106 include a plurality of holes 104, 108, respectively, for balancing the fan 86 during rotation. In addition, the center of mass for the fan 86 can be altered by an interruption region 110 that is located between fan blades 98 opposite the lower counterweight 106. The illustrated interruption region 110 is defined by ridges 112 that have a short height relative to the height of the fan blades 98, which results in a reduced mass relative to the fan blades 98. The ridges 112 can be formed by reducing the height of one or more fan blades in the interruption region 110, or by molding the ridges 112 during formation of the fan 86. By removing or reducing the mass within the interruption region 110, the center of mass of the fan 86 can be calibrated to provide the balanced performance of the sander 10. For example, the size of the interruption region (i.e., the quantity of ridges 112) within the region 110 can be adjusted to reduce vibration or improve overall user control of the sander 10. Furthermore, altering the fan's 86 center of mass by removing mass, or enlarging the region 110—rather than adding mass—mitigates the need to evenly add mass to both counterweights 102, 106, which can increase costs or change the dimensions of the sander 10. The reduced height of the ridges 112 within the interruption region 110 also have minimal to no impact on the dust collection efficiency of the fan 86, especially when compared to other conventional orbital sanders having fans without the interruption region 110. The height of the illustrated ridges 112 in the interruption region 110 is approximately 1 millimeter, although other relatively short heights are possible and considered herein.

FIGS. 3 and 5A-5B illustrate a dust collection system 120 in accordance with an embodiment of the sander 10. The dust collection system 120 includes upper and lower sections 136, 140 with an upper shroud portion 132 and a lower shroud portion 134, respectively, that cooperate to form a shroud portion 130 that surrounds the fan 86. The lower shroud portion 134 partially encloses the fan blades 98 from the underside, and the upper shroud portion 132 partially encloses the fan blades 98 from the opposite side. The upper shroud portion 132 has projections or extensions 133 that partially enclose one face side of the fan 86, and the lower shroud portion 134 has a circumferential projection or extension 135 that cooperates with the extensions 132 to form a seal 160 between the housing 14 and the fan 86.

Each of the upper and lower sections 136, 140 can be fastened together by a plurality of fastening points 152 and/or corresponding form fit features 156, 158 located on the respective sections 136, 140. In some embodiments, the fastening points 152 can be connected using conventional fasteners, such as screws, a snap-fit arrangement, or a combination of both. The dust collection system 120 also includes a mating interface 124 that is formed completely by the lower section 140 to selectively receive a dust bag attachment 128. The dust bag 128 can be mounted to the interface 124 via a latching mechanism 144 that hooks onto a latch 125 present on the surface of the interface 124.

During operation of the sander 10, the suction generated by the fan 86 sucks dust through the plurality of holes 52 (FIG. 3 ) in the baseplate 46 and routes the dust along a dust path 148 into the shroud 130. After the dust enters the shroud 130, the dust circulates around the shroud 130 until it eventually is routed along the path 148 through the interface 124 and into the dust bag 128 for collection. The seal 160 creates a vacuum effect resulting in little to any dust escaping into the housing 14 as the dust is circulating in the shroud 130. This vacuum effect within the shroud 130 results in a stronger suction force that yields a higher dust collection efficiency relative to conventional orbital sanders.

FIGS. 6A-6B illustrate a front clamp 38 in accordance with an embodiment of the sander 10. The front clamp 38 includes a main body 40 that has a center portion 41 and winged portions 45 a, 45 b, and a torsion spring 47 pivotably mounted to the baseplate 46 and in contact with the main body 40 of the clamp 38. Each of the winged portions 45 a, 45 b are supported by a respective stop feature 51 mounted on the baseplate 46. The stop features 51 are configured to prevent the winged portions 45 a, 45 b of the clamp body 40 from flexing during installation/removal of the sanding sheet 164 (FIG. 7 ). Additionally, the stop features 51 provide an added level of rigidity to the clamp 38, which improves the clamping force between the sanding sheet 164 and the clamp 38 for stronger paper retention. Furthermore, in the event a user should drop or misuse the sander 10, the stop features 51 preclude the winged portions 45 a, 45 b from flexing to the point where the sander 10 can be potentially damaged.

With reference to FIGS. 3, 6A-6B, and 7 , the sanding sheet 164 is retained on the sander 10 by pivoting the center portion 41 of the front clamp 38 relative to the baseplate 46 from the orientation shown in FIGS. 6A, 6B with help from the bias of the torsion spring 47. Next, the user inserts the sanding sheet 164 underneath the clamp 38 and raises the body 40 of the clamp 38 onto the sanding sheet 164 to retain the sheet 164 in the front clamp 38. After the sanding sheet 164 is retained in the front clamp 38, the user lifts the rear clamp 42 out of its groove 43 within the baseplate 46, thereby releasing a rear clamp body 44. Then, the user wraps the sanding sheet 164 around the foam pad 50 and the baseplate 46 and moves the sanding sheet 164 between the rear clamp body 44 and the baseplate 46. Lastly, to completely retain the sanding sheet 164, the user moves the rear clamp 42 back into its groove 43 on the baseplate 46 to clamp the sanding sheet 164 between the rear body 44 and the baseplate 46.

FIG. 7 illustrates the foam pad 50 in accordance with an embodiment of the invention. The foam pad 50 is retained on the bottom of the baseplate 46 by a plurality of fasteners (e.g., screws, not shown) and acts as a retention surface for the sanding sheet 164 when it is clamped between the front and rear clamps 38, 42. The foam pad 50 is structured so that there is some degree of overhang 172 relative to the baseplate 46. This overhang 172 acts as a barrier, or buffer, between the baseplate 46 and a work surface 168. During flush sanding, where the sanding sheet 164 is pressed directly up against the work surface 168, the overhang 172 prevents any scuffs or other damage to the work surface 168 that would otherwise might have occurred between surface-to-surface contact between the hard surface of the baseplate 46 and the work surface 168. In some embodiments of the sander 10, the foam pad 50 can include the overhang 172 on three sides of the sander 10 for safe contact between the sanding sheet 164 and the work surface 168. The overhang 172 can be 1.5 millimeters, or larger or smaller than 1.5 millimeters.

FIGS. 8A-8B illustrate a battery receptacle 26 in accordance with an embodiment of the invention. The battery receptacle 26 is structured such that a lower portion 29 of the receptacle 26 creates a gap 200 between the battery pack 31 and the receptacle 26 when the battery pack 31 is mounted to the sander 10. In particular, the lower portion 29 defines a plane P that is obliquely oriented with respect to a battery pack insertion axis B. The plane P and axis B define therebetween an included angle A between 0 and 5 degrees, and in some embodiments, the angle A is greater than 5 degrees but less than 10 degrees. In some embodiments, the angle A is 4.9 degrees. Essentially, the battery pack 31 is cantilevered from the battery receptacle 26 so that no portion of the battery pack 31 directly contacts the receptacle 26 or the motor housing 18. By eliminating the direct contact points between the battery pack 31 and the receptacle 26, the vibrations carried by the motor housing 18 to the receptacle 26 during use of the sander 10 are not transferred, at least in any significant way, to the battery pack 31. More particularly, this configuration attenuates and/or eliminates the chattering of the battery pack 31 from the vibration between the battery pack 31 and the receptacle 26, which allows the user a more pleasant experience when operating the sander 10.

FIG. 9 illustrates an alternative drive unit 254 for use with the sander 10 of FIGS. 1-3 . Like components and features of the sander 10 of FIGS. 1-3 will be used “plus” 200. The drive unit 254 includes an electric motor 258 having a motor shaft 259 for rotatably driving a first pulley 255, a second pulley 257 rotatably coupled to a drive shaft 262 and parallel with the first pulley 255, and a belt 260 tensioned by the first and second pulleys 255, 257, which transmits the torque from the motor shaft 259 to the drive shaft 262. The drive unit 254 further includes a first bearing 274 for supporting a top portion of the drive shaft 262 configured to be retained in the motor housing 18, and a second bearing 278 for supporting a lower portion 264 of the drive shaft 262. The second bearing 278 is captured by a baseplate carrier 248 formed on the baseplate 246 and the lower portion 264 of the drive shaft 262 is fastened to the baseplate carrier 248 by a fastener 249 (e.g., a screw, not shown) such that the drive shaft 262 is coupled the baseplate carrier 248 for relative rotation. The drive unit 254 also includes a plurality of torque absorbers 282 located on the baseplate 246. The torque absorbers 282 flex and absorb the torque from the motor 258 to prevent free rotation about a rotational axis 266. A fan 286 with a plurality of fan blades 298 is positioned on the lower portion 264 of the drive shaft 262 between the second bearing 278 and the drive shaft 262 for generating a sufficient suction force to draw in dust and debris through a plurality of holes 252 in the baseplate 246 during operation of the sander 210. To help balance the fan 298 during operation, the fan 298 includes top and bottom counterweight 302, 306. In some embodiments of the drive unit 254, the fan 298 includes fan blades 298 on both the top and bottom sides of the fan 298.

In some circumstances, it is advantageous to implement the drive unit 254 in the sander 10 because the orientation of the drive unit 254 relocates the center of gravity 400 of the sander 10 closer to the center of the baseplate 246 relative to conventional orbital sanders with a direct drive system. Because the center of gravity is located further inward from the edges of the baseplate 46, there is a reduced likelihood that the sander 10 could tip over when the battery pack 31 is mounted on the receptacle 26. In addition, by locating the motor 258 offset from the drive shaft 262, the sander 10 feels more balanced during use when compared to use of conventional direct-drive orbital sanders. Furthermore, the drive unit 254 allows the user to customize the gear ratios of the pulleys 255, 257 to ensure the maximum efficiency for the selected size and type of electric motor 258. For example, the user can customize the gear ratios of the pulleys 255, 257 such that the drive unit 254 is more efficient than a comparable direct-drive sander using the same size and type of electric motor. Therefore, the belt drive unit 254 allows the same sized orbital sander to have a longer runtime when compared to the same sized direct-drive orbital sanders.

Various features of the invention are set forth in the following claims. 

What is claimed is:
 1. An orbital sander comprising: a housing; a drive unit within the housing, the drive unit including an electric motor defining a rotational axis, a drive shaft coupled for co-rotation with the motor about the rotational axis, the drive shaft including a lower portion, and a fan rotatably coupled to the lower portion of the drive shaft, the fan including a main body having a plurality of fan blades, an upper counterweight located on one side of the main body and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan, and an interruption region located opposite the lower counterweight, wherein the fan blades located within the interruption region have a reduced mass; and a baseplate for selectively mounting a sanding sheet, the baseplate being coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.
 2. The orbital sander of claim 1, further comprising a motor housing for housing the electric motor; a battery receptacle for selectively receiving a battery pack to provide electrical power to the motor; and a dust collection portion integrated with the housing for partially housing a dust collection system.
 3. The orbital sander of claim 2, further comprising a paper retention system including a front clamp supported on the baseplate, and a rear clamp supported on an opposite side of the baseplate as the dust collection portion.
 4. The orbital sander of claim 1, wherein the fan blades located within the interruption region have a height of 1 millimeter.
 5. The orbital sander of claim 2, wherein the dust collection system includes a shroud portion for partially enclosing the fan blades to form a seal between the housing and the fan blades, and a mating interface having a latch for selectively receiving a dust bag attachment.
 6. The orbital sander of claim 5, wherein the dust collection system further includes a latching mechanism that hooks onto the latch on the mating interface to selectively secure the dust bag attachment.
 7. The orbital sander of claim 3, wherein the paper retention system further includes one or more stop features mounted to the baseplate for preventing flexion of the front clamp.
 8. The orbital sander of claim 2, wherein the battery receptacle defines a battery insertion axis, and wherein the battery pack receptacle includes a lower portion that defines a plane obliquely oriented with respect to the battery insertion axis to create a gap between the battery pack and the battery receptacle when the battery pack is mounted to the battery receptacle, the plane and battery insertion axis defining therebetween an included angle between 0 and 10 degrees.
 9. An orbital sander comprising: a housing; a drive unit within the housing, the drive unit including an electric motor defining a rotational axis, a drive shaft coupled for co-rotation with the motor about the rotational axis, the drive shaft including a lower portion, and a fan rotatably coupled to the lower portion of the drive shaft; and a dust collection portion integrated with the housing for partially housing a dust collection system, the dust collection system including a shroud portion for partially enclosing the fan to form a seal between the housing and the fan, a mating interface having a latch for selectively receiving a dust bag attachment, and a latching mechanism for hooking onto the latch to secure the dust bag attachment; and a baseplate for selectively mounting a sanding sheet, the baseplate being coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.
 10. The orbital sander of claim 9, wherein the seal creates a vacuum effect routing dust particles along a dust path through the interface and into the dust bag attachment.
 11. The orbital sander of claim 9, further comprising a motor housing for housing the electric motor; and a battery receptacle for selectively receiving a battery pack to provide electrical power to the motor.
 12. The orbital sander of claim 9 further comprising: a paper retention system including a front clamp supported on the baseplate, and a rear clamp supported on an opposite side of the baseplate as the dust collection portion.
 13. The orbital sander of claim 9, wherein the fan further includes a main body having a plurality of fan blades, an upper counterweight located on one side of the main body and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan, and an interruption region located opposite the lower counterweight, and wherein the fan blades located within the region have a reduced mass.
 14. The orbital sander of claim 12, further comprising a foam pad attached to the baseplate for supporting the sanding sheet, wherein the foam pad extends beyond one or more sides of the baseplate acting as a buffer between the baseplate and a work surface.
 15. The orbital sander of claim 13, wherein the fan blades located within the interruption region have a height of 1 millimeter.
 16. An orbital sander comprising: a housing; a drive unit within the housing, the drive unit including an electric motor having a motor shaft extending from the motor, a drive shaft coupled to the motor and offset from the motor shaft, the drive shaft defining a rotational axis and including a lower portion, and a fan rotatably coupled to the lower portion of the drive shaft, the fan including a main body having a plurality of fan blades; an upper counterweight located on one side of the main body and a lower counterweight located on an opposite side of the main body for balancing the operation of the fan; and a baseplate for selectively mounting a sanding sheet, the baseplate being coupled to the lower portion of the drive shaft for orbital rotation about the rotational axis.
 17. The orbital sander of claim 16, further comprising a first pulley rotatably driven by the motor shaft; a second pulley coupled to the drive shaft oriented parallel to the first pulley; and a belt extending between the first and second pulleys for transmitting torque from the motor shaft to the drive shaft.
 18. The orbital sander of claim 16, wherein the fan further includes an interruption region located opposite the lower counterweight, and wherein the fan blades located within the interruption region have a reduced mass.
 19. The orbital sander of claim 16, further comprising a motor housing for housing the electric motor; and a battery receptacle for selectively receiving a battery pack to provide electrical power to the motor.
 20. The orbital sander of claim 19, wherein when the battery pack is mounted to the battery receptacle, the center of gravity is located substantially over a center of the baseplate. 